Facile Synthesis of High‐Quality Cu–Cd–Mg Spinel Chromite Thin Film for Enhanced Ultraviolet Photodetectors

In this study, the Cu 0.4 Cd 0.3 Mg 0.3 Cr 2 O 4 spinel chromite compound was prepared through the sol–gel synthesis technique, and its structural, elastic, and optical behaviors were thoroughly investigated. X‐ray diffraction analysis (XRD) verified the successful formation of a pure cubic spinel phase, while Fourier‐transform infrared (FTIR) spectra exhibited distinct vibration bands associated with metal–oxygen bonds at the tetrahedral and octahedral coordination sites within the lattice. The calculated elastic constants indicated a brittle mechanical behavior with isotropic elastic characteristics. Optical investigations exhibited broad UV–Vis absorption bands with a direct optical band gap of 2.23 eV and a low Urbach energy of 0.91 eV, suggesting minimal structural disorder. A thin film of Cu 0.4 Cd 0.3 Mg 0.3 Cr 2 O 4 fabricated via spin coating displayed remarkable UV photodetection performance. Electrical measurements revealed a pronounced photocurrent enhancement under UV illumination, with rapid response times of 0.85 s (rise) and 1.36 s (decay) at a bias voltage of 1 V. Furthermore, the device exhibited a detectivity ( D *) of 5.86 × 10 10 Jones and a responsivity ( R ) of 11.78 A/W, comparable to high‐performance UV photodetectors. The obtained results confirm the potential of Cu–Cd–Mg spinel oxide for efficient UV photodetection and optoelectronic technologies.